First Alert SMICO100, Battery-Operated Combination Smoke & Carbon Monoxide Alarm, 1-Pack

Easy to install. Works great! Bought these to replace our old one that was many years old. This is a good brand.

worked like a charm and easy to install.

Purchased for RV and although thicker than one replaced, still fit fine. There is a plug so could be integrated to other detectors, which I did not do. Actually bought the used option VS new, to save a few $$. Used was in OEM package with instructions and a battery. The rear of package was sealed with tape, but other than that we would not know it from new unopened. Totally pleased with used purchase, the detector and entire process.

Good value I’ve had several for many years. They work well. I write on them when they’re installed with a sharpie and change them out as recommended.

I copy and pasted two reviews already posted because both are true. Device may be great but the package did not include connectors. These do not fit the device they are replacing, don't know why the proper connectors are not included. I had the same model already in the house so I assumed the new ones would fit with no problem. I was soooo wrong, when I got them I saw the connectors are different which makes no sense if you are replacing the same model. If they changed the way it connects they should put the new type of connectors in the box or mention that the old version can’t connect to the new one. So if you want to install you need to buy those separately which is ridiculous.